Joint hypermobility syndrome/Ehlers-Danlos syndrome hypermobility type (JHS/EDS-HT) is a largely unrecognized, heritable connective tissue disorder, mainly characterized by joint instability complications, widespread musculoskeletal pain, and minor skin features. In a case-control study, 47 consecutive JHS/EDS-HT patients were investigated for the prevalence of psychiatric disorders and compared to 45 healthy controls in a single center. The psychiatric evaluation consisted of structured clinical interview for DSM-IV criteria by using the SCID-I and the SCID-II. Symptom severity was assessed using the Hamilton Anxiety Rating Scale (HAM-A), the Hamilton Depression Rating Scale (HAM-D), and the Brief Psychiatric Rating Scale (BPRS). The Global Assessment of Functioning Scale (GAF) was used to assess the overall severity of psychological, social, and occupational functions. JHS/EDS-HT patients had significantly higher mean scores for all questionnaires: HAM-A (6.7 vs. 3.8), HAM-D (6.4 vs. 2.7), GAF (75.0 vs. 86.1), and BPRS (27.5 vs. 25.6). The JHS/EDS-HT group had a 4.3 higher risk of being affected by any psychiatric disorder, and in particular, a 5.8 higher risk of having a personality disorder. In particular, 5 JHS/EDS-HT suffered from obsessive-compulsive personality disorder with an observed prevalence rate of 10.6 % (3.6-23.1). Psychiatric assessment of JHS/EDS-HT patients showed an extremely high prevalence of personality disorders (21 %), and of Axis-I disorders (38 %), mostly depressive. This study did not confirm the previously reported increased rate of panic disorders in JHS/EDS-HT.